IGFBP3 and nonpapillary renal cell carcinoma: Among the many validated HRGs, we decided to further analyze the contributions to tumor growth by VEGF, Cyclin D1 (CCND1), ENOLASE2 (ENO2), EGLN3, ANGPTL4, GLUT1, and IGFBP3, because they are involved in many well-known aspects of HIF biology but their roles were not directly investigated in a ccRCC xenograft model.